Why? Why do people do this? This article mentions these "botmasters" but doesn't say why these people do these things. It didnt seem to me like there was money involved. I can't understand why anyone would do these things that sound like they take a long time to create. Please, help me out here.
I don't get it.

There's a tremendous amount of money in spam. If I control a massive botnet capable of sending millions or billions of emails a day, I can then charge spammers to distribute their message.

If I can turn my bot army on a site and shut it down through a denial of service attack, I can also extort money from businesses by threatening to knock them off the grid.

Thank you, I knew there had to be money involved somewhere.

I don't think there's really that much money there. My guess would be no more than a few tens of million dollars for the entire worldwide spam/extortion "industry". The problem is that it's really quite easy and cheap to write and distribute an Internet worm, and there is no risk of going to jail over it if you're in the right country, so it's worth doing it even for a few thousand dollars. But the scale of the Internet means such a crime costs the world many billions of dollars in lost productivity and in deploying technical defenses and cures.